Why Can Phones Fold

Core Materials of Flexible Displays

1. OLED Technology

The main display technology used in foldable smartphones is Organic Light-Emitting Diodes (OLED). Compared to traditional Liquid Crystal Displays (LCD), OLEDs offer advantages such as self-illumination, thinness, lightweight, and high contrast. More importantly, OLED screens can achieve a high degree of flexibility, ensuring excellent display performance even after multiple folding and unfolding cycles.

2. Flexible Substrates

The backplane material of OLED displays typically uses flexible substrates, such as Polyimide (PI) films. This material boasts extremely high flexibility and heat resistance, capable of withstanding frequent bending without cracking or performance degradation. The application of flexible substrates is fundamental to enabling screen foldability.

High-Strength Protective Layers

Ultra-Thin Glass

To protect the flexible OLED screen, many foldable smartphones adopt Ultra-Thin Glass (UTG). Compared to traditional glass, UTG is thinner and has a certain degree of flexibility, allowing it to maintain screen rigidity while permitting some bending. The use of UTG effectively enhances the screen’s durability and scratch resistance.

Bendable Plastic Materials

Some foldable smartphones opt to use bendable plastic materials, such as Polyethylene Terephthalate (PET) or Thermoplastic Polyurethane (TPU), as the screen’s protective layer. These materials exhibit higher flexibility, capable of enduring a wider range of folding angles, but they may be slightly inferior to ultra-thin glass in terms of scratch resistance and transparency.

Advanced Hinge Mechanisms

The hinge mechanism of foldable smartphones is equally crucial. High-precision hinge designs allow the phone to fold and unfold smoothly while ensuring screen alignment and stability. Modern hinges typically employ precise mechanical engineering designs combined with lightweight materials, such as titanium alloy or stainless steel, ensuring that the hinge performs excellently even after multiple uses.

Flexible Circuits and Conductive Materials

To ensure that electronic components function normally during the folding process, foldable smartphones use flexible circuits. These circuits utilize liquid metal or conductive ink as conductive materials, offering high plasticity and conductivity. Liquid metals, such as gallium-based alloys, can maintain stable electrical conductivity when bent, while conductive inks form complex circuit patterns by printing on flexible substrates.

Manufacturing Processes and Technology

The manufacturing process of foldable smartphones involves multiple advanced technologies, including precise semiconductor manufacturing processes, high-precision mechanical machining, and nanoscale material processing. These processes ensure the perfect integration of various materials and the overall reliability of the device.

Conclusion

The emergence of foldable smartphones relies on the synergistic action of various advanced materials and precise technologies. From flexible OLED displays and ultra-thin glass protective layers to liquid metal flexible circuits and high-precision hinge mechanisms, each material and technology ensures that the phone can be folded repeatedly while maintaining excellent performance and user experience. With continuous technological advancements, future foldable smartphones will become even more lightweight and durable, becoming a significant direction in the development of smartphones.